FIG. 6 illustrates an example of a conventional semiconductor light emitting device (see e.g. Patent Document 1). The illustrated semiconductor light emitting device X includes a lead frame 91, an LED chip 92, a case 93 and a light transmitting member 94. The lead frame 91 includes two frame elements 91A and 91B. The first frame element 91A is thicker than the second frame element 91B. The LED chip 92 is mounted on the obverse surface of the first frame element 91A. The LED chip 92 is connected to the second frame element 91B via a wire 95. The case 93 is made of e.g. a white resin. The light transmitting member 94 fills the space in the case 93 to cover the LED chip 92. The light transmitting member 94 is formed with a lens 94a for enhancing the directivity of the light emitted from the LED chip 92.
When the semiconductor light emitting device X is in operation, heat is generated at the LED chip 92. Since the heat hinders the stable operation of the semiconductor light emitting device X, the heat needs to be dissipated from the LED chip 92. To increase the thickness of the first frame element 91A may be a useful measure to promote the heat dissipation from the LED chip 92. However, to increase the thickness of the frame element 91A leads to an increase in the entire size of the semiconductor light emitting device X.    Patent Document 1: JP-A-2007-67443